Merge tag 'drm-misc-next-2018-09-19' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for 4.20:

UAPI Changes:
- None

Cross-subsystem Changes:
- None

Core Changes:
- Allow drivers to disable features with per-device granularity (Ville)
- Use EOPNOTSUPP when iface/feature is unsupported instead of
  EINVAL/errno soup (Chris)
- Simplify M/N DP quirk by using constant N to limit size of M/N (Shawn)
- add quirk for LG LP140WF6-SPM1 eDP panel (Shawn)

Driver Changes:
- i915/amdgpu: Disable DRIVER_ATOMIC for older/unsupported devices (Ville)
- sun4i: add support for R40 HDMI PHY (Icenowy)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Icenowy Zheng <icenowy@aosc.io>
Cc: Lee, Shawn C <shawn.c.lee@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20180919200218.GA186644@art_vandelay

drivers/gpu/drm/i915/intel_display.c

@@ -6685,22 +6685,20 @@ intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den)
 
 static void compute_m_n(unsigned int m, unsigned int n,
 			uint32_t *ret_m, uint32_t *ret_n,
-			bool reduce_m_n)
+			bool constant_n)
 {
 	/*
-	 * Reduce M/N as much as possible without loss in precision. Several DP
-	 * dongles in particular seem to be fussy about too large *link* M/N
-	 * values. The passed in values are more likely to have the least
-	 * significant bits zero than M after rounding below, so do this first.
+	 * Several DP dongles in particular seem to be fussy about
+	 * too large link M/N values. Give N value as 0x8000 that
+	 * should be acceptable by specific devices. 0x8000 is the
+	 * specified fixed N value for asynchronous clock mode,
+	 * which the devices expect also in synchronous clock mode.
 	 */
-	if (reduce_m_n) {
-		while ((m & 1) == 0 && (n & 1) == 0) {
-			m >>= 1;
-			n >>= 1;
-		}
-	}
+	if (constant_n)
+		*ret_n = 0x8000;
+	else
+		*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
 
-	*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
 	*ret_m = div_u64((uint64_t) m * *ret_n, n);
 	intel_reduce_m_n_ratio(ret_m, ret_n);
 }
@@ -6709,18 +6707,18 @@ void
 intel_link_compute_m_n(int bits_per_pixel, int nlanes,
 		       int pixel_clock, int link_clock,
 		       struct intel_link_m_n *m_n,
-		       bool reduce_m_n)
+		       bool constant_n)
 {
 	m_n->tu = 64;
 
 	compute_m_n(bits_per_pixel * pixel_clock,
 		    link_clock * nlanes * 8,
 		    &m_n->gmch_m, &m_n->gmch_n,
-		    reduce_m_n);
+		    constant_n);
 
 	compute_m_n(pixel_clock, link_clock,
 		    &m_n->link_m, &m_n->link_n,
-		    reduce_m_n);
+		    constant_n);
 }
 
 static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)